Electric switch



y 2, 1933- w. F. HELMOND 1,906,588

ELECTRIC SWITCH Original Filed Dec. 11, 1926 2 Shets-Sheet 1 In ven far:

y 1933' w. F. HELMOND 1,906,588

I ELECTRIC SWITCH Original Filed Dec. 11. 1926 2 Sheets-Sheet 2 Patented May 2, 1 933 1 WILLIA 1*. HEL'MOND, or WEs'r mn'rro'nn,coNNEo'rIoU'nAssIGiIoR "r0 UNDERwooD ELLIOTT FISHER COMPANY, ornnwyonmn; Y;, A CORPORATION'OF DELAWARE L, nLEo'rnrc SWITCH f i ori inara ncati n fileii pecember 11, 926, Serial in); 154,107, meme m1. 1,835,776, dated December 8,1931. Divided; and this application filed Jaly 14,;1930. Serial No. 4 7,726."

This invention relates to typewriting machines, and more particularly to means fol" returning the typewriter-carriage by power. .A finger-piece at the keyboard controls an arm' of a novel electric switch, said'arm beingthrown into circuit making position bya spring which is controlled by a pawl A worm-shaft of a motor-drive effects an engagement of clutch-members, whereupon V c a. carriage-return rack first effects the lineattached to aystandard Underwood typespacing, and then thereturnfof the carriage. Means are'carried by the carriage to throw'iout the switch-arm at thecompletion of the return of the carriage, or at writing machine with a minimum of changes and addltions.

r The switch includes a circuit'anak'er and breaker, in the form of 'aswinging contactarm,monnted and controlled in such a man-' nert o be free from spark1ng,no1seless'in action, andrcapable of rapid manipulation.

Saidkeyboard .finge'r piece or key engages a slide carrying a by-pass pawl, the latter coacting with the contact-arm .to first move" said arm rearwardly against aspring, .tensioning the spring which becomes effective a 5;; on the further movement ofthe slide and bypass pawl, to release the arm, and then,

under the force ofthe releasedspring tenslon said arm is thrown into contact with-c by any means, or by the returning carriage and its connections. The finger key must be returned and the by-pass pawl resume 1tsf normal position before the repeating of a switch-closing action cantake' place. This becomes important in a short return stroke of the carriage, since in suclrwork the op-f erator may have pressed downthe key,"and

ber l1,1926 (now Patent the switch: may not have been: r'eleasedin some cases. 5 1 I a The disconnection of the contact-arm, from the; switch by the returnv ofthe carriage, to open the circuit, is effected by a stop-member on the carriagewhichengages a dog carried the right-hand marginal stop, 'said do'g coacting with a rocking switch release frame,.one end of which car- ,j

ries a depending. link, effective to throw outthe contact-arm of theswitch, at intermediate stations. The contact-arm is re leased to open the. circuit for the final or 0 position of the carriage,'by the marginal stop-release lever that is mounted on the earriage. a r 1 y a One, feature of the present invention is the provision of a switch-mechanism operated by a finger-key associated with means for preventing" a repeat action of the switch contact arn of the "switch-mechanism, while f the operator holds the finger-key depressed.

The closing of the circuit for the second cycle of operation cantake place only aftertlie return of the fingerekeyg I e a This application is a division of my application, SerialNo. 154,107, filed Decem-,

1 No. 1,835,776,dated' Dece1nber"8, 1931.) p Other features 'and'advantages will hereinafterap'pear;

In the accompanying drawings,

,Figure 1 is a perspective-view of a portion ofa typewriter embodying the princi pal improvements.

lcas'e mechanism. 1

F1gure3 1s a detail 1n Figure -&'is a rear view, of the switch-i x mechanism' in the same positions shown in while the contact-arlnmay be dlseonnected Figureti. a a Figure 5 is a vicwrsimilar to Figure 4,

with the switch mechanism and the vconmam-n1 in closed circuit position.

' Figure 6 is a perspective v ew of; the.

switch-mechanism, showing the contact-arm Y 1 F1gure'2'1s a plan showlnga switch-reperspective ofa "t' f'h l-l f TBy the use of this by pass mecham-sm the: pol Ion 0 e re ease Mme in open circuitposition and its immediate connections; a

' Figure 7 is'a'detailperspective view,

group, showing the component parts of the switch-contact-arm.

Figure 8 is a perspective view, in group, showing the contact-members and their connecting leaders.

Figure 9 is a sectional view (enlarged) of the contact-arm assembled.

Figure 10 is a longitudinal sectional view (enlarged) of the switch-block.

Figure 11 is a detail perspective view of the switch-block and contact members.

Figure 12 is an under side view of the switch-block and the connecting leaders to the contact-arms.

In the practice of my invention, a carriage 10 of an Underwood typewriting machine in which the invention is embodied is supported in the well-known manner to travel along the machine for letter-spacing on a rear rail (not shown) and a front rail. 11 secured on the main frame 12.

For returning the carriage there is provided a carriagewack-bar 13 which meshes with a pinion 14 driven by a motor 15, and suitable clutchemechanism is interposed between the motor and pinion, so that the pinion may be either connected to the motor or disconnected therefrom.

The motor 15 is located at the rear of the machine and is attached to a bracket lGof a housing 17 supported on the main frame 12.

A switch 18 is located at the left on a bracket 19 of frame 12, above the keyboard and below the supporting rods of the carriage-marginal-stop-members. A connection from below is made by a key-lever 2,0 and slide-member 21 to throw in a; pivoted switch contactarm 34- to close the motorcircuit.

The switch 18 includes a, body or frame 23 having an, arm 24 held to bracket 19-of frame 12 by. screws 25.

The bracket 26 is bent to provide a. Wa1l28, in which thereis a. guide slotf29to receive the end of the slide 21, which; isfurtherslide is bent to make contact withthe innen end of the key-lever 20. The upper. end of the slide has a shouldered portion 31, be tween which and the inner side of wall 28 a spring 32 is held, andprovides for a return motion of the slide after its upward stroke effected by key-lever 20. Bracket 26 on which is pivoted the switch contact-ar1n 34, in position to be thrown into contact with a pair of contact-members 35 and 36 on a block 37of insulation.

The switch contact-arm 34 is not directly moved into engagement with the contact members 35 and 36. A spring, actuator 38 The body 23has. a guide bracket 26 fastenedby a: screw 27..

is employed and operated by the slide 21. For this purpose the slide has an extension 39 carrying a by-pass pawl 40, the end of which engages a wing 41 of the switch contact-arm 34. Normally the switch contactarm 34 hangs downward (Figure 4), and the slide 21 in its lowermost position with the by-pass pawl thereon engages the wing 41 on the switch contact-arm 34 and on the upstroke of the slide 21 the spring actuator 38 is forced rearwardly, as in Figure 5 (broken lines), tensioning the spring actuator by the rearward action of the switcharm, which engages a hooked end of the spring actuator 38 and is carried rearward therewith. hen the slide 21 approaches the end of its upward stroke, imparted by the key-lever 20, the by-pass pawl passes clear of the wing 41 on the switch-arm, the tensioned spring actuator 38 is released, and the arm 34 is thereby thrown into contact position between the contacts 35 and 36.

The extension 39 of the slide 21 extends upward, and the top end has a screw 42.

around which is coiled a spring 43, one end reaching downward into an opening of. the bypass pawlv to urge the pawl toward the wing 41, of switch-arm, 34,, and against a stop 44 on the slide 21. The other end of spring 43 is caught over. the switch-arm. 34, holding it lightly against the hooked end of. the spring actuator38, thereby preventing the arm from vibrating or. arring into contact or sparking relation. with the switchcontact-members 35 and 36. when. the slide 21. isin its normal position. Spring 43, be ing mounted one slide 21, travels with the same, thus removing the tension. onv switcharm34, whenithe switchis operated and permits the, switch-arm to travel unencumbered by tension of? spring 43.v In. other words, spring 43 holds down. the switch-arm only when slide 2l i's in normal position.

The spring actuator 38 of suitable-wire fastens under the screw-head 27, of the bracket 26by aloop in the spring, both ends of the wire passing into a perforation of the bracket; 26, thereby holding the loop from spreading under the screw-head, and forming a fulcrum-point forthe tensioning of one-end of the-spring actuator when being forcedlbaclnvardby the by-pass pawl; The spring actuator 38 in its normal position formsa stop for the-return of switch-arm 34:?VV1IE11 the-armis out of: contact.

The switch-aria 34 (Figures 8 and 9) is p insulated from the body ofthe switch 23 by extends down and carries a pivot-screw 33' providing the arm 34 with contact-portions 45-and 46 insulated from the arm itself by non-conductive washers 47 and 48, the portion-45 having a head and a stem passing through washer- 47,.the latter having a re Vducedpartfitting in opening of arm 34, the

washer. 48 fittingon reduced part ofrwasher 47 andTthe contact 46.0nstem of contact 45 held together as in Figure 9 by heading over the stem ofcontact 45. Insulated block: 37 to whichthecontact-members and 36 are attached for engagement with the-arm 34 to close the line-circuit, isprovided with a head 49 wherein is locatcd'a pair ofcircuitrline connecting bushings 50 held by set=screws-5l.

The bushings 50 are threaded to'receive binding screws 52,-that serve asterminals to attach line wires, Leaders 53 and 54 are located below the surfac'eat the under side of the'block 37 in'recesses or channels 55, one end of the leaders being held to the bushings 50by'screws 56 and carried back through the "channels to- 'the opposite end of the block 37 to a similar" head perforated to re ceive a flanged bushing 57 of non-conductive materiah The leaders 53 and 54 have bent offset portions also perforated to receive thebushing 57 J Theleader 53 has its bent offset end folded closeto the top of-the'block 37, on top of which is located theeontact-member*35,the position of which will be in a plane with one side of the pivoted contact arm 34. The leader 54is similarly bent, but provides room between the bent portion for an insulating spacer58 of such thickness as to providesuflicient space for the proper entrance of the contact 'arm 34 between the I passing between the leaders into the frame 23.

The key-lever 20 for operating the slide 21 is preferably mounted on the same pivot center as that of the lock-release lever-shaft 61 of the typewriter on the left side of the machine. The lock-release lever-shaft 61 is shortened and the pivot-screw is threaded into the frame 12, and a reduced diameter of the screw passes throughthe hub of the keylever and into the end of the lock-release lever-shaft, thereby holding the key-lever in that engages the slide 21 down and clear of the slide.

From the foregoing it will be seen on the depression of the key-lever 20, the slide21 with the by-passpawl thereon is actuated to effect contact between the contact-members 35 and 36 by pivoted contact-arm 34, closing the motor-circuit. Upon'the return of the carriage,the switch-arm 34 is released from the contacts 35 and 36 as the carriage reaches the end of its travel, either at thefinal stop gaged by a'lug v68 on the carriage to throw the front ofthe dog downward, which front end 69 rides on a rail of a switch-release frame 70. The latter is mounted to rock on the rod 65, on a pairof corresponding arms 71 extending forward, one at each end of the rail, and an arm 72 reaching rearward in position above the switch. A lmk 73 is pivoted at 74 to the arm 72and extends down, the free end entering the switch-frame 23, passing into a slot 75 in the wall 28 of the bracket '26. The end of the link is in position to engage the switch-arm 34'at the top thereof, on the rockingof the frame to throw the arm 34 out of contact with the members 35 and 36. The dog 66'may be turned over on its pivot tobe out of the path of the lug 6S onjthe carriage, and the carriage will'then travel to the full or home position. At this final stop position, the

switch-release frame 7 O is rocked by the bent end 76 of the right-hand marginal release lever 77, engaging a cam-projection 78 formed on the end of the rail of the switchrelc'ase frame, which looks the frame, and, as

before,throws out the arm 34. To return,

the frame 70 to; normal position, and the link 73 clear of theswitch-arm 34, a spring 79, coiled about the rod 65, rocks the frame back, the rail of which engages the main frame 12' asastop. f

Briefly stated, the operation of the inech'a nism is as'foliows On depression of the type-keys the carriage moves step by step,

actuated by the usual spring.- When the end of the line is reached, the operator depresses the" carriagemeturn key 20. p This lifts the slide 21 of the switch, and, through the by-pass pawl 40, shifts rearwardly the switch contact arm 34 against spring 38. At ascertain point in the slide travel, the bypass pawl releases the arm 34, and the spring 38 throws the arm into circuit between the contact-members 35' and- 36, whereupon the motor is set in motion and the carriage re turned to a predetermined stopping position. At this time, the carriage'is stopped at a right-hand marginal-stop position, and the lug 68on the carriage will engage dog 66, the latter engaging the rail of the switchrelease frame 70, rocking itdownward; and the link- 73 thereon engaging the switch contaet-arm and forcing it out of its closed-cirouit position, whereupon the motor sto iis.

The same operation takes place when the carriage returns to its initial or Olposi tion, exceptthat the cam 78 on the switchrelease frame is engaged by the bent end 76 of the marginal-stop release lever 77 instead of the dog 66 on the marginal stop.

v Variations may be resorted to within the scope of the invention, and portions of the in'iprovements may be used without others.

Having thus described my invention, I claim:

1. An electric switch including a normally ineffective swingable contact-arm, a normally untensioned spring, an operating key, means operated by said key to swing said arm against said spring to tension the latter, and a trip to break the connection between said means and said arm to permit the tensioned spring to swing the contact-arm to effective position.

2. An electric switch to open and close a motorcircuit, including a pivoted switcharm, a switch-arm operating spring, a keyactuated trip operable to swing said arm to tension said spring, and then release said arm to enable the spring to effect a quick movement of said arm to effective position, and means dependent upon the functioning of the motor, for causing the arm to open the switch.

3. An electric switch including a pivoted contact-arm, a normally ineffective spring, a key, a slidable member operated by said key, and a member pivoted upon said slide and effective upon operation of said slide to swing said switch-arm to cause it to tension said spring, said arm being self-releasing from said pivoted member, to permit said spring to snap said arm to effective position.

4. An electric switch including a pivoted contact-arm, a normally ineffective spring, a key, a slidable member operated by said key, and a'trip mounted on said slidable member effective during the initial movement of said key to swing said switch-arm and cause the arm to tension said spring, and effective upon further depression of said key to release said arm and permit said tensioned spring to swing said arm to effective position.

5. An electric switch to energize a motor for returning the carriage of a typewriting machine, said switch including a pair of terminals in the form of clamping jaws, a pivoted switch-arm to be moved into and out of engagement with said jaws for making and breaking the electric circuit, a normally ineffective switch-arm operating spring, a key, a slidable member operated by said key, a latch carried by said member, and means to cause said latch to swing said arm against said spring to tension the same, said means including an automatic trip to release said arm and permit said spring to impart a swinging movement to said arm of sufficient momentum to cause said arm to enter the clamping jaws of said terminals.

6. An electric switch for energizing a motor to return the carriage of a typewriting machine, including a key, a slide operated by said key, a pawl carried by said slide, a switch-armfor making and breaking an electric contact, means 011 said arm to cooperate with said pawl to swing said arm during the initial movement of said key, and a normally untensioned spring, said spring being tensioned during the initial swinging of said arm, said arm being selfreleasing from said pawl to permit said tensioned spring to swing said arm from ineffective to effective position.

7. An electric switch for energizing a motor to return the carriage of a typewriting machine, including a key, a slide operated by said key, a pawl carried by said slide, a switch-arm for making and breaking an electric contact, a projection on saidvarm to eo-operate with said pawl to swing said arm during the initial movement of said key, and a normally untensioned spring, said spring being tensioned by said arm during the initial swinging of said arm, said arm being self-releasing from said pawl to permit said tensioned spring to impart a fast swinging movement of said arm in the reverse direction for making the electric contact.

8. A normally open electric switch to close a motor-circuit, including a normally idle pivoted switch-closing arm, a normally idle spring to swing said arm to close the circuit, a key, a trip driven by said key to retract said arm to tension said spring, means being provided to release the trip from the arm at the key-stroke, and means being also provided, dependent upon the functioning of' the motor, for retracting the arm to open the switch.

WILLIAM F. HELMOND. 

